This is a competitive renewal application for a post-doctoral Cardiovascular Training Grant (CVTG) Program centered at Tufts Medical Center (Tufts-MC) and Tufts University School of Medicine (TUSM). This CVTG provides state-of-the-art training to outstanding postdoctoral M.D. and/or Ph.D. fellows and is exemplary of the approach that the NHLBI seeks for training the next generation of CV scientists. Two broad and overlapping types of mechanistic CV research are emphasized: (1) cellular and molecular investigations of the CV system; and (2) translational, clinical studies in CV medicine. In its first five-year cycle this CVTG Program has been highly successful with 20 trainees to date, 43 peer-reviewed articles published by trainees, and two CVTG graduates now with K-grant funding. Several integrated elements make this CVTG Program a highly unique, multidisciplinary training experience: the rich training environment of the Tufts Health Sciences Campus, which includes Tufts-MC, TUSM, the Tufts Sackler Graduate School of Biomedical Sciences and the Tufts Human Nutrition Research Center, the internationally recognized Molecular Cardiology Research Institute, a major CV research department at Tufts-MC with 17 Pis and ~100 people, and the Tufts-MC Cardiology Division, with a superb group of translational researchers; the extensive portfolio of NIH-funded CV research in CVTG faculty; new training resources from the recent CTSA award; and the world-class faculty, with highly evolved collaborative interactions especially in this CVTG Program. Additional important strengths of this revised CVTG application include: 1. a special emphasis on mentoring, with each trainee being mentored by a 3-member mentoring committee with expertise spanning basic, clinical, and translational approaches, 2. a strong commitment to recruitment of highly qualified minority trainees, and 3. the inclusion of a strong and broad core curriculum. Trainees and faculty are formally evaluated on an annual basis. This program trains 4 postdoctoral M.D. and/or Ph.D. fellows per year for three years (steady-state: 12 trainees/year), with the goal of producing independent cardiovascular scientists well-equipped to lead their own research programs.